code: def __call__(self, num_update, backbone: torch.nn.Module):
      if self.rank is 0 and num_update > 0:
          backbone.eval()
          self.ver_test(backbone, num_update)
          backbone.train()
  
file_path: insightface/recognition/arcface_torch/utils/utils_callbacks.py
imports: import logging
  import os
  import time
  from typing import List
  import torch
  from eval import verification
  from utils.utils_logging import AverageMeter
  from torch.utils.tensorboard import SummaryWriter
  from torch import distributed
label_desc: Use image node_id 4 for calling the CallBackVerification obj's underlying member method code with example usage: obj.__call__(num_update, backbone) without return types